Production of long chain alkyl substituted aromatic hydrocarbons



United States Patent PRODUCTION OF LONG CHAIN ALKYL SUB- STITUTEDAROMATIC HYDROCARBONS Robert A. Sanford, Park Forest, and Bernard S.Friedman, Chicago, lll., assignors to Sinclair Refining Company, NewYork, N. Y., a corporation of Maine No Drawing. Application April 1,1954, Serial No. 420,446

4 Claims. (Cl. 260-671) Our invention relates to the production of longchain alkyl substituted aromatic hydrocarbons which have particularvalue in the production of oxidation-stable alkyl aromatic acids anddetergent compositions. More particularly, our invention relates to theproduction of such alkyl aromatics in which the alkyl group contains atleast 8 carbon atoms by the alkylation of aromatic hydrocarbons withscission-susceptible olefins in the presence of aluminum halidecatalysts.

Long chain alkyl aromatic hydrocarbons are conventionally produced bythe alkylation of an aromatic hydrocarbon, e. g. benzene, in thepresence of an alkylation catalyst such as aluminum chloride. When thealkylation is carried out with a straight chain olefin, the olefinremains intact and the desired long chain alkyl aromatic hydrocarbon isproduced with no difliculty. Scissionsusceptible polyolefins, such asdiisobutylene, may also be used to react with more reactive aromaticnuclei such as phenol to produce long chain alkyl aromatics. When,-however, the scission-susceptible olefins are reacted with monocyclicaromatic hydrocarbons such as benzene or toluene, the olefin apparentlyundergoes extensive polymerization and depolymerization or cleavageprior to alkylation and the resulting product is a mixture of alkylaroma tic hydrocarbons containing new side chains both lower and higherin aliphatic molecular weight than the olefin originally used. Thisdegradation of the olefin also results in the production ofsubstantially inseparable poly-alkylated aromatics of the same molecularweight and boiling range as the desired alkyl aromatic. For example,when benzene is alkylated with diisobutylene under normal alkylationconditions, the olefin appears to undergo depolymerization prior toalkylation and the final product consists mainly of short chain monoanddi-tertiary butylated benzene rather than long chain octylated benzene.This is very undesirable, as sulfonation of this mixture produces lowyields of sulfonates which are poor in detergent quality and whichrequire costly purification to eliminate or reduce odor, unsulfonated'residue and color bodies. Because of this difiiculty, processes dealingwith the production of long chain alkyl aromatics for detergentmanufacture by the alkylation of aromatics with an olefin specify thatthe olefin be substantially free from scission-susceptible olefins suchas isobutylene polymers or copolymers.

We have now found that valuable long chain alkyl substituted monocyclicaromatic hydrocarbons in which the alkyl group contains at least 8carbon atoms are produced in good yields by the alkylation of thearomatic hydrocarbon with scission-susceptible olefins containing atleast 8 carbon atoms in the presence of catalysts comprising aluminumhalides by controlling the temperature between about -65 to -l C. Bycontrolling the temperature sufiiciently low, cleavage of the olefin isavoided. Thus, toluene is octylated or dodecylated with vdiisobutyleneor triisobutylene respectively, or select cleavage-alkylation occursresulting in the production of alkyl aroma- 2,810,769 Patented Oct. 22,1957 tics in which the alkyl group contains at least 8 carbon atoms, forexample, octylation of toluene with tetraisobutylene. Undesirableclefava ge resulting in the formation of short chain butylated productsis substantially avoided and formation of undesirable short chain andpolymer products is kept to a According to our invention, a monocyclicaromatic'hydrocarbon is reacted with a scission-susceptible olefin inthe presence of a catalyst comprising aluminum halide while controllingthe temperature between about 65 to 15 C. At higher temperatures,excessive butylation occurs and at lower temperatures excessivepolymerization occurs with little intact alkylation. The reaction isstopped, for example, by quenching with water, the product is washedwith Water or alkali solution, dried and the products recovered bydistillation.

Generally, the catalyst and aromatic are mixed and then contacted withthe olefin. The manner of contacting is important in that abnormalorientation and cleavage reactions may occur with alkylation productswhile the addition of the olefin to the catalyst and aromatic mixture isbeing completed. We have found that keeping the olefin concentration lowduring alkylation and keeping additional contact time after olefinaddition to a avoids abnormal orientation and cleavage reactions andresults in the production of high yields of the desired alkyl aromatic.Thus, slow addition of the olefin with early quenching of the reactionis preferred procedure. Advantageously, two streams, one containingaromatic hydrocarbon and the olefin and the other aromatic hydrocarbonand catalyst, are directed into a mixing chamber and after a shortcontact time discharged into a stream of water to stop the reaction.Commercially, a suspended catalyst can be employed and the catalystseparated just before quenching by gravity separation or centrifugationand recycled. The molar ratio of aromatic to olefin to catalyst may varyfrom about 46:0.5l.5 :0.08-0.3. Preferably, the ratio is 5:l:0.l. n V

By the process of our invention, readily available scission-susceptibleolefins can be employed as the olefin source without losses andcomplications previously encountered in alkylation reactions witharomatic hydrocarbons because of cleavage reactions, to produce,selectively, valuable alkylated aromatics, some of which are novelcompounds. The novel compounds produced by our invention aretertiary-alkylated monocyclic aromatic hydrocarbons, i. e. benzene andsaturated hydrocarbon substituted benzenes, in which the tertiary-alkylradical is of a particular type and which contains at least 8 carbonatoms, particularly from 8 to 20 carbon atoms. The tertiary-alkylradical of our novel compounds is a radical in which all methylene(CHz-,-) or methinyl groups are attached to at least two quaternarycarbon atoms.

The novel compounds include, for example, tertiaryalkylated benzencssuch as t-dodecyl benzene or 2,2,4,6,6- pentamethyl-4-phenylheptane;tertiary-alkylated toluenes such as t-octyl-toluenes or paraormeta-(1,1,3,3-tetramethylbutyl) toluenes, t-dodecyl-t'olu'enes or2,2,4,6,6- pentamethyl-4- (paraor meta-tolyl) heptanes,t-hexadecyltoluenes or 2,2,4,6,6, 8,8-heptamethyl-4-(paraor metat'olyl)nonanes; tertiary-alkylated dimethylbeuzenes such asdimethyl-(t-dodecyl)-benzenes or 2,2,4,6,6-pentamethyl-4-(3,4- or3,5-dimethylphenyl)-heptanes, dimethyl- (thexadecyl)-benzenes or2,2,4,6,6,8,8-heptamethyl-4 (3,4 or 3,5-dirnethylphenyl)-nonanes;tertiary alkylated octyl toluenes such as di-t-octyl-t-oluene or,di-'(:1,1,3,3- tetramethylbutyl) -toluene;' V and tertiary-alkylated;octyl benzenes' such as 1,4-di (t-octyl )-benzene or 1,4-di

7 least tw'oou'at'ernary carbon atoms(1,1,3,3-tetramethylbutyl)'-benzene. By our invention not only one buttwo or more of long chain :alkyl groups such as t-octyl, t-dodecyl andt-hexadecyl can be attached m a t c. h r a bq filsa a sr s a i 4 inim; oq vme is roduce "h alkyl aromati s areuse ful s such ori asjchemicalalkyl subslituent s to p roduce oxidation-stabletertiary alkylatdtriinesic, athniaeq enzon acids useful in greases and,-w;henes'terified, in plasticizers and resins.

'The s tructure "of the tertiary-allcyl group of our novel com nsateprovides advantageous oxidation resistance in that all methyleneormethinyl groups are attached to at For example, the tertiary groups -thetertiary-octyl and tertiar'y-nonyl aromatics of o'u'r invention havethe'following structure:

7 C C I V m m G (I -C -+-aromatie V i V who s or 1 o o e V f -dljO-aromatic (1) I Ihus,' the JQ DQQHY vulnerable position s in themethylene oup of t e e i y-mal d al a P it ss in the methinyl group ofthe tertiary-nonyl radical ,are protected by the adjacent quaternarygroups which effectively preyent .attaclg by oxidative reagents byivirtue of their bulk,

' n olvin s r c 9 spatia nd ancci contra-st, tertiery-alk l'groupsof'terti'ai'yalkylated aromatics in which the group icontains exposedsecondary hydrogens"( in methylene groups and exposed tertiary hyrq ep t1 s?tll r u lr g oup r s i to o i at a a h Fo e am l h fo o n t t ylklated a omatics a e sub e t to same a ta h lil t la s his t kem mala sei a isobutylene, for example, diisobutylene, triisobutylene andtetraisobutylene, polymers of isoamylene, isohexylene :and isoheptyleneas well as eo-polymers of isobutylene with propylene, n-butylene oramylene, and their hydrogen halide adducts. The ease of alkylationWithoutundesirable cleavage varies with the molecular weight of theolefin. Thus, alkylation without undesirable cleavage is more difficultwith the hig her molecular weight olefins than with diisobutylene, forexample, but such alkylation can be effected. V

By 'monocyclic aromatic hydrocarbons, useful for alkylation according tothe process of our invention, we

i mean benzene and saturated hydrocarbon substituted benzenes, i. e.alkyl and cycloalkyl substituted benzenes preferably containingnot'morethan 12 carbon atoms in the alkyl or cycloalkyl group. For example,toluene, buty-lbenzene, cyclohexylbenzene, octylbenzene,dimethylbenzene, r( sth lqyclmen )begzeae cl hex t l fi; otyltohieae, ad kmthlwsb e )t uen a e useful subs titiited *benz enes. The easeofallcylationvaries with the type or substitution in the benzene ring,usually decreasing in reactivitytfor example, in the following bvderi ia t lu e b nze e ut benz fie an coi The aromatics are also useful, forexample, in the elec- "matics :for sulfonation to producedetergents,wetting agientizind'ernulsifyihg"agents, including synthetic oil-'soluble sulfonates. addition, nitration and reduction V of thesearomaticslyield useful amines-tor surfaetiye agentsand inhibitors; I V 7I l By scission-susceptible olefins, we means ,olefins, or

their hydrogen'halide 'additioi'products,"containing at -least 8'carblon atoms which tend, to emerge cleavage undernormal alkyl a'tionconditionsI 'lhe :mostfuseful scission-susc'eptible folefins contain'from 8 to 2 0 carbon benzene. V

By aluminum halide catalysts, we mean aluminum chloride or aluminumbromide, either unpromoted or promoted by the additionof thecorresponding hydrogen halide. Aluminum;halide-hydrocarbon complexessuch as that formed in the alkylation process, or produced separately:by mixing and/or heating the aluminum halide with extraneoushydrocarbons, may be employed for the alkylation reaction. V V V T Inthe alkylation, thetemperature required within the range'ot to l5 C. foroptimum alkylation minimum undesirable cleavage and polymer formationvaries with the catalyst, the'reactivity of the" aromatic and the olefin,usedi -For' exaniple, inithe presen ce of uupromoted aluminum chloride,optimum octyl ation" of toluene with diisobutylene occurs at about +35to" 2 0 G. With benzene, however, a less reactive aromatic, optimumoctylation occurs at a higher t einperature, i. e.

about -20 to 15- C, In the 1alkylationof benzeng the V benzenejisadvantageously dissolvedi n a solvent such as n-pentane orjn heptane tomaintain solution, When the hydrogen halide addition product of theolefin is used for alkylation, generallylower temperatures are required.For example, t-dodecylchloride and toluene give high yields ofdodecyl-toluene, and t-hexadecyl chloride and are required for optimumalkylation without undesirable cleavage thantwhen using annnp'romote'dcatalyst. *rer example, optimum octylation of toluene withdiisqbutylene' occurs at about +65? C. in the pres encefof analuminumchloride catalyst promoted with hydrogen chloride.

With benzene, however, such low temperatures arenot ie quired andoptimum octylation is obtained with a temperature range of about -40 to-20 C., particularly about -35 C.' The hydrogen -halide additionproducts of the olefin may-be used itdesiredand require temper 'aturesjA A V a The process of our invention will befurther illustrated by thefollowing examples. 7

N i I Ek ampleI.

A four-necked iluted flask was fitt d with a-V'stirrer,

idrdbpiiigifuimeli e mga s and r fl x s ndenss 1191;1-

' ing a calcium chloride drying tube An isopropanol bath m w th an e aed i p halide catalysts promoted with a hydrog'en halide are employed,generally lower temperatures peratures. Eleven gramsof aluminum chloridecatalyst were added at 30 C. to 460 grams of toluene in the flask and tothis stirred mixture were added 112 grams of diisobutylene over a periodof 170 minutes while maintaining the temperature at 30 C. Stirring wascontinued for 60 minutes after addition of the olefin while maintainingthe termperature at C. The reaction was stopped by quenching thehydrocarbon layer with water. The alkylation products were washed withwater and sodium bicarbonate solution, dried over anhydrous potassiumcarbonate and fractionally distilled. The distilled products wereexamined using an infrared spectrophotometer.

The products, based on the Weight percent of olefin converted, were 28.5percent para-t-octyl and 24.5 meta-- t-octyl toluene, 14.9 percentpara-t-dodecyl and 5.9 percent meta-t-dodecyl toluene and only 6.1percent t-butyl toluene. No polymer was formed.

Example 11 Using the procedure of Example I, the same proportions ofaluminum chloride, toluene and diisobutylene were reacted. The catalystwas added at C. and the olefin was added over a period of 30 minutes andstirring was continued for 60 minutes. The reaction temperature wasmaintained at 34 C. The products, based on the weight percent of olefinconverted, were 45.4 percent t-octyl toluene, 25.4 percent t-dodecyltoluene, 23.8 percent para-t-hexadecyl toluene and only 6.5 percentt-butyl toluene. No polymer was formed.

The para-(t-hexadecyl) toluene or 2,2,4,6,6,8,8-heptamethyl-4-(p-tolyl)nonane was examined to determine its physical properties. The compoundhad a boiling point of 200 C. at 30 mm. and was a gel at roomtemperature. The refractive index (n 25/ D) was 1.4893 and the specificgravity (d 20/4) was 0.8730.

Example Ill Using the procedure of Example I, the same proportions oraluminum chloride, toluene and diisobutylene were reacted. The catalystwas added at 35 C. and the olefin was added over a period of 34 minutesand stirring was continued for only 6 minutes. The reaction. temperaturewas maintained at 35 C. The products, based on the weight percent olefinconverted were 69.7 percent para-t-octyl and 9.9 percent meta-t-octyltoluene and only 4.7 percent para-t-butyl and 1.3 percent metat-butyltoluene. No polymer was formed. The high yield of t-octyl toluene showsthe advantage of slow addition of the olefin with early quenching of thereaction.

The para-(t-octyl) toluene or p-(1,l,3,3-tetramethyl butyl) toluene wasexamined to determine its physical properties. The compound had aboiling point of 249 C. at 760 mm. and a melting point of l0 C. Therefractive index (n 25/D) was 1.4939 and the specific gravity (d 20/4)was 0.8736. A molecular weight of 200, 88.1 percent carbon and 11.8percent hydrogen were found which closely corresponds to the calculatedmolecular weight of 204.3, percent carbon of 88.1 and percent hydrogenof 11.9 for the formula CrsHzr.

Example IV Using the procedure of Example I, 11.7 grams of aluminumchloride were added at -20 C. to 460 grams of toluene. 224 grams oftetra-isobutylene were added to the stirred mixture over a period of 60minutes and stirring was continued for 60 minutes. The reactiontemperature was maintained at 35 C. The products, based on the weightpercent olefin converted, were 62.5 percent para-t-octyl, 3.9 percentmeta-t-octyl and 1.4 per cent octyl toluene, 10.1 percent dodecyltoluene, 16.0 percent para-hexadecyl toluene nad only 4.6 percentt-butyl toluene. No polymer was formed. Thus, select cleavage of the C16olefin was obtained to produce a good yield of t-octyl toluenes.

Example V Using the procedure of Example I, 11.1 grams or. aluminumchloride were added at 20 C. to 390 grams of benzene in 270 grams of ann-pentane diluent. 112

grams of diisobutylene were added to the stirred mixture Example VIUsing the procedure of Example I, 4.8 grams of a.lu minum chloride wereadded at 20" C. to 154 grams of toluene. 50 grams of t-octyl chloridewere added to the stirred mixture over a period of 30 minutes andstirring was continued for 60 minutes. The reaction temperature wasmaintained at 60 C. The products, based on the weight percent alkylchloride converted, were 16.9 percent para-t-octyl and 51.1 percentmeta-t-octyl toluene and only 11.2 percent t-butyl toluene.

The meta-t-octyl toluene or m-(1,1,3,3-tetramethy1- butyl) toluene wasexamined to determine its physical properties. The compound had aboiling point of 118 C. at 15 mm. and 242 C. at 760 mm. and was a gel atroom temperature. The refractive index (n 25/D) was 1.4937.

Example VII Using the procedure of Example I, 11.5 grams of aluminumchloride were added at 20 C. to 460 grams of toluene and 3 grams of HClwas passed into the mixture. 112 grams of diisobutylene were added tothe stirred mixture over a period of 50 minutes and stirring wascontinued for 40 minutes. The reaction temperature was maintained at 65C. The products, based on the weight percent olefin converted, were 61.6percent para-toctyl and 10.9 percent meta-t-octyl toluene, 20.6 percentpara-t-dodecyl and 4.1 percent meta-t-dodecyl toluene and only 3.1percent t-butyl toluene and 2.9 percent polymer.

Example VIII Using the procedure of Example I, 5 grams of aluminumchloride were added at 0 C. to 156 grams of benzene in 120 grams ofn-pentane. 81.6 grams of tdodecyl chloride were added to the stirredmixture over a period of minutes and stirring was continued for 30minutes. The reaction temperature was maintained at 40 C. The products,based on the weight percent olefin converted, were 26.7 percent octylbenzene, 3.5 percent di-tbutyl and 25.3 percent t-dodecyl benzene.

The t-dodecyl benzene or 2,2,4,6,6-pentamethyl-4- phenyl heptane wasexamined to determine its physical properties. The compound had aboiling point of 297 C. at 760 mm. and was a gel at room temperature.The refractive index (n 25/D) was 1.4921 and the specific gravity (d20/4) was 0.8693. 87.7 percent carbon and 12.7 percent hydrogen werefound which closely agrees with the calculated percent carbon of 87.7and percent hydrogen of 12.3 for the formula C13H30.

Example IX Using the procedure of Example I, 6 grams of aluminumchloride were added at 45 C. to 39 grams of benzene in 187 grams of ann-pentane diluent. 112 grams of t-octyl chloride were added to thestirred mixture over a period of minutes and stirring was continued for10 minutes. The reaction temperature was maintained at 45 C. Theproducts, based on the weight percent olefin converted, were 13.4percent t-octyl benzene, 11.2 percent octyl benzene, 4.4 percentdi-t-butyl benzene, 19.4 percent dodecyl benzene, 30.8 percentdi-t-octyl benzene and 1.6 percent dioctyl benzene. No butyl benzene wasformed.

' The di-t-octyl benzene or;1,4 di-(1,1,3,3-tetramethylbutyl), benzenewas examined to determine its physical propjertiesi- The comgeurrdhad aboiling 'point'of 329 'C. at'766 iirirn-.' arid a gel at roomtemperature. The

' r'fractiye in'deii (n 25713) was 1.4959 and the specific gra ityld2074)] was 0.8831. A rnolecular weight of 297, 87I1ipe1fentf carbonfland12.4 percent hydrogen were foundwh'ichlclos'ely agrees, with thecalculated molecular weight of 3025, percent carbon of 87.3 and percenthy drogjnofl2r7 for' the formula CzzHss.

f ,fExan tple X 7 Using the procedure of Example 1; 12 grams of aluminumchloride were added at 30 C. to 460 grams of toluene. 168 grams oftriisobutylene were added to the stirred mixture over a'period of 30minutes and stirring was continued for 60 minutes. The reactiontemperature was niaifitaified'at' GS C. Theproducts, based on theweightpercent'olefin converted, were 8.0 percent p'ara-tocftylltolun'e,1.6 percent meta-t-octyl' toluene, 24.3 perclent para-t-dodec'yl toluene.or 2,2,4,6,6-pentamethyl-4- (p-tolyllheptane, 2.0 percentmeta-t-dodecyl toluene, 7.9 percent p'ara-hexadecyl toluene,39L0'percent polymer and only 12.6 percent t-butyl toluene.

' 'We' claim:

I. A process 'for the production of long chain tertiary alkylsubstituted monocyclic aromatic hydrocarbons in which the alkyl groupcontains from 8 to 20 carbon atoms, which comprises reacting amonocyclic aromatic hydrocarbon selected fi omsthe group consisting of;benzeneiand-z toluene.- with. a scission susceptible tertiary olefin,selectedz from the group consistingof polymers'of isobutylenegcontaining from 8' to 20 carbon-atomsand'their hydrogen halide additionproductsin the presence of acatalyst 001111-- prising aluminum chloridewhile controlling the tempera.

* toluene with. a polymer of isobutylene containing from- 8 to 20 carbonatoms in the presence of an aluminum;chlow;v ride catalyst whilevcontrolling the temperature at about ReferencesCitedin the file of thispatent UNITED STATES PATENTS.

2,072,153 Bruson f Mar. 2, 1937' 2,232,117 Kyrides' Feb. 18', 1941.2,437,356 Hill Mar. 9, 1948' 2,456,119 7 Friedman et al. Dec. 14, 1948'2,673,224 Kennedy et' a1 Mar. 24, 1954'. 2,768,985

Schlatter Oct. 30, 1956 1

1. A PROCESS FOR THE PRODUCTION OF LONG CHAIN TERTIARY ALKYL SUBSTITUTEDMONOCYCLIC AROMATIC HYDROCARBONS IN WHICH THE ALKYL GROUP CONTAINS FROM8 TO 20 CARBON ATOMS, WHICH COMPRISES REACTING A MONOCYCLIC AROMATICHYDROCARBON SELECTED FROM THE GROUP CONSISTING OF BENZENE AND TOLUENEWITH A SCISSION-SUSCEPTIBLE TERTIARY OLEFIN SELECTED FROM THE GROUPCONSISTING OF POLYMERS OF ISOBUTYLENE CONTAINING FROM 8 TO 20 CARBONATOMS AND THEIR HYDROGEN HALIDE ADDITION PRODUCTS IN THE PRESENCE OF ACATALYST COMPRISING ALUMINUM CHLORIDE WHILE CONTROLLING THR TEMPERATUREAT ABOUT -65* TO -15*C.